1. Field of the Invention
The present invention relates to an electron emission device and an electron emission display employing the same. In particular, the present invention relates to an electron emission device having enhanced electron emission uniformity.
2. Description of the Related Art
In general, electron emission devices refer to devices that extract electrons from a cathode electrode, hot or cold, into vacuum. Such devices may be combined with a light emission unit and an anode electrode to form electron emission displays.
Electron emission devices employing cold cathodes refer to devices having cathode electrodes that, instead of employing heat, emit electrons by application of a strong electric field, i.e., drive voltage, between the cathode and gate electrodes. An arrangement of a plurality of such cathode and gate electrodes on a substrate with electron emission regions therebetween may form an electron emission device. The arrangement of cathode and gate electrodes with electron emission regions therebetween may also be referred to as electron emission elements, while overlapping regions of the cathode and gate electrodes may be referred to as pixel units. Electron emission elements in cold cathode electron emission devices may include Field Emitter Array (FEA) elements, Surface Conduction Emitter (SCE) elements, Metal-Insulator-Metal (MIM) elements, and Metal-Insulator-Semiconductor (MIS) elements.
The drive voltage applied between the cathode and gate electrodes should be stable to minimize voltage difference, i.e., voltage drop, between electron emission regions of the pixel units to provide uniform electron emission, and, subsequently, uniform light emission in the pixel units. Such voltage stability may be achieved by increasing the number of electron emission regions at each pixel unit or application of a resistive layer between the cathode electrode and the electron emission region in order to control an intensity of the current. In particular, the cathode electrode may include first and second electrodes attached to the same plane and interconnected by a resistive layer, such that the electron emission region may be formed on either the first or the second electrode.
However, when a resistive layer is employed in conventional electron emission devices, the first electrode may be provided with contact openings, such that an effective width, i.e., an electrode width contributing to a current flow in a unit pixel, of the first electrode may be reduced, thereby increasing a line resistance of the first electrode relative to that of the second electrode. Such a difference in line resistance between the first and second electrodes may reduce the electron emission uniformity despite the use of a resistive layer, thereby decreasing the light emission uniformity in the pixel units along the length of the first electrode of the electron emission display.
Accordingly, there exists a need to improve the structure of the electron emission device in order to provide sufficient voltage stability therein and maintain proper light emission uniformity and electrical operation of the electron emission display.